Added functionality to synchronize access token refresh across multiple tabs using the `navigator.locks` API. This prevents race conditions when refreshing tokens, ensuring that a newer token published by another tab is reused instead of rotating the refresh token unnecessarily. Introduced a new method `refreshAccessTokenAcrossTabs` and updated the `getOrRefreshAccessToken` function to utilize this new method. Enhanced error handling for 401 responses to retry with the latest stored token when applicable.
